1. Field of the Invention
This invention relates generally to shim devices, and more particularly to a shim device having a resilient envelope enclosing a viscous putty material.
2. Brief Description of the Prior Art
Very often, objects such a tables and chairs are supported on an uneven surface, or they have legs of different lengths which causes them to suddenly tilt. Furniture is often chocked with various objects, such as leveling screws, folded paper, bottle caps, and other miscellaneous material at hand. Although these objects may work for a limited time, they are unsightly and undesirable. Others have devised complicate mechanisms in an attempt to solve this problem. There are several patents which disclose various furniture leveling devices and other mechanical devices utilizing bouncing putty.
Hinman, U.S. Pat. No. 3,827,663 discloses a self adjusting furniture support comprising a foot member spring biased in a downward direction along a rectilinear guideway extending at an angle from the horizontal plane.
Ball, U.S. Pat. No. 4,798,359 discloses a self adjusting furniture glide having an upper body rotatably mounted to a lower foot piece having an arcuate ramp surface on which a complimentary ramp surface of the upper body rests, and a coil spring mounted between the foot and upper body to downwardly bias the foot piece and to apply a torque which opposes mutual rotation of the pieces.
Blake, U.S. Pat. No. 3,244,382 discloses an apparatus for resisting a sudden pull in one direction on a flexible member comprising a housing, a drum on which the flexible member is wound, first and second rotatable elements mounted in the housing and arranged to engage bouncing putty located between them. The bouncing putty is put in shear when the elements rotate relative to one another. When a predetermined rate of relative movement is reached, the resistance to shear of the bouncing putty is increased and the elements tend to rotate together.
Brooks, U.S. Pat. No. 3,382,511 discloses a safety cushion having a rigid bottom wall, rigid side walls extending upwardly from the bottom, and a mass of bouncing putty occupying the entire space between the bottom and side walls. The bouncing putty filled cushion provides a custom fit for the user and but becomes rigid and unyielding under a rapidly applied load.
Brooks, U.S. Pat. No. 3,606,463 discloses a vehicular seating system comprising a rigid backing member and a cellular cushion of elastomeric material having a plurality of voids which are filled with bouncing putty resiliently contained therein by the elastomeric material. The original configuration of the seating system is maintained by the elasticity of the cushion and is rendered substantially rigid during sudden acceleration.
Wigal, U.S. Pat. No. 3,871,496 discloses a rate controlling device which is attached to a moving element for controlling the rate of motion of the moving element. Bouncing putty is enclosed in a flexible envelope and force is applied thereto substantially equal to the driving force applied to the moving element. When the moving element is speeded up, the resistance applied by the flexible envelope increases greater than proportionally to the force exerted thereon due to the properties of the bouncing putty.
The present invention is distinguished over the prior art in general, and these patents in particular by a self adjusting shim device having a elastic outer bladder formed of resilient material filled with bouncing putty. The bouncing putty filler will deform slowly under the slightest force like a highly viscous liquid but will resist rapidly applied loads as if it were a solid. The shim device is placed between the bottom of and article, such as one or more legs of a piece of furniture, and the weight of the article supported on the shim device will, in a short time, cause the shim device(s) to deform and the article supported will assume a state of equilibrium, even if the legs are of unequal length. A sudden downward force applied to the supported article will create a compressive force on the resilient bladder causing the bouncing putty filler to become rigid and resist the downward force. When the downward force is lessened or removed, the bladder tends to return to its original shape. In another embodiment, the elastic bladder is contained within a pair of opposed rigid cup-shaped members telescopically joined together and adapted to be installed on the bottom of articles. The self adjusting shim device substantially reduces or eliminates the tilting or wobbling action of the articles under which it is placed and will compensate for the unevenness of floors or legs of unequal length. They may also be applied to heavy machinery and washing machines, etc., to reduce vibration and their tendency to "walk" when in operation.